806 research outputs found
Star products, duality and double Lie algebras
Quantization of classical systems using the star-product of symbols of
observables is discussed. In the star-product scheme an analysis of dual
structures is performed and a physical interpretation is proposed. At the Lie
algebra level duality is shown to be connected to double Lie algebras. The
analysis is specified to quantum tomography. The classical tomographic Poisson
bracket is found.Comment: 22 pages, no figure
Classical mechanics is not h=0 limit of quantum mechanics
Both the set of quantum states and the set of classical states described by
symplectic tomographic probability distributions (tomograms) are studied. It is
shown that the sets have common part but there exist tomograms of classical
states which are not admissible in quantum mechanics and vica versa, there
exist tomograms of quantum states which are not admissible in classical
mechanics. Role of different transformations of reference frames in phase space
of classical and quantum systems (scaling and rotation) determining the
admissibility of the tomograms as well as the role of quantum uncertainty
relations is elucidated. Union of all admissible tomograms of both quantum and
classical states is discussed in context of interaction of quantum and
classical systems. Negative probabilities in classical mechanics and in quantum
mechanics corresponding to the tomograms of classical states and quantum states
are compared with properties of nonpositive and nonnegative density operators,
respectively.Comment: 14 pages, to appear in Journal of Russian Laser Res.(Kluwer Pub.
Duality symmetry for star products
A duality property for star products is exhibited. In view of it, known
star-product schemes, like the Weyl-Wigner-Moyal formalism, the Husimi and the
Glauber-Sudarshan maps are revisited and their dual partners elucidated. The
tomographic map, which has been recently described as yet another star product
scheme, is considered. It yields a noncommutative algebra of operator symbols
which are positive definite probability distributions. Through the duality
symmetry a new noncommutative algebra of operator symbols is found, equipped
with a new star product. The kernel of the new star product is established in
explicit form and examples are considered.Comment: 14 pages, no figure
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